ABSTRACT
Lasers are used increasingly in the surgical field. As far as plastic surgery is concerned, CO2 lasers are the most frequently used lasers especially in removing superficial skin lesions. But the traditional continuous mode CO2 lasers causes thermal injury in the surrounding tissues by heat diffusion, thus preventing the widespread clinical use. However, CO2 lasers of the continuous mode are being replaced by pulsed type, which emit high-energy pulse in a short period of time. Keeping the pulse length below the thermal relaxation time, these pulsed CO2 lasers vaporize tissues with less thermal injuries in the surrounding tissues. We irradiated Clearpulse and Ultrapulse lasers on the back of two swine models, Seven spots with 3 mm diameter were measured. We observed the histological changes of injuries and regeneration, and analyzed the depth of the thermal injury and the thickness of the regenerating epidermis quantitatively with image analyzer according to the time sequence(immediate, 1 day, 3 days, 1 week, 2 weeks, 3 weeks, 4weeks). In Clearpulse group, there was epidermolysis and the depth of thermal injury was 432 +/- 12.7micrometer, whereas in Ultrapulse group, the epidermis showed just coagulation necrosis and the depth of thermal injury was measured as 217 +/- 8.7micrometer. Clearpulse group showed the healing pattem of dermis, while Ultrapulse group showed the healing pattern of epidermis. That means Ultrapulse group is superior to Clearpulse group considering healing time. But all specimens obtained the complete healing of skin around 4th week after ablation.